/*
 * Kodkod -- Copyright (c) 2005-present, Emina Torlak
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package kodkod.util.ints;

/**
 * A skeletal implementation of the IntCollection interface.
 *
 * @author Emina Torlak
 */
public abstract class AbstractIntCollection implements IntCollection {

    /**
     * Constructs an empty int collection.
     *
     * @ensures this.isEmpty()
     */
    protected AbstractIntCollection() {}

    /**
     * {@inheritDoc}
     *
     * @see kodkod.util.ints.IntSet#isEmpty()
     */
    @Override
    public boolean isEmpty() {
        return size() == 0;
    }

    /**
     * Iterates through this.ints and returns true if it finds i, otherwise returns
     * false.
     *
     * @return true if i is in this collection, otherwise returns false.
     */
    @Override
    public boolean contains(int i) {
        for (IntIterator iter = iterator(); iter.hasNext();) {
            if (i == iter.next())
                return true;
        }
        return false;
    }

    /**
     * Throws an UnsupportedOperationException.
     *
     * @throws UnsupportedOperationException
     */
    @Override
    public boolean add(int i) {
        throw new UnsupportedOperationException();
    }

    /**
     * Iterates through the elements of this, removes i if it finds it and returns
     * true. Otherwise returns false. Throws an UnsupportedOperationException if
     * this.iterator() does not support removal.
     *
     * @ensures iterates through the elements of this and removes i if it finds it
     * @return true if this collection has changed as a result of the call
     * @throws UnsupportedOperationException this.iterator() does not support
     *             removal
     */
    @Override
    public boolean remove(int i) {
        for (IntIterator iter = iterator(); iter.hasNext();) {
            if (i == iter.next()) {
                iter.remove();
                return true;
            }
        }
        return false;
    }

    /**
     * {@inheritDoc}
     *
     * @see kodkod.util.ints.IntCollection#containsAll(kodkod.util.ints.IntCollection)
     */
    @Override
    public boolean containsAll(IntCollection c) {
        if (size() >= c.size()) {
            for (IntIterator itr = c.iterator(); itr.hasNext();) {
                if (!contains(itr.next()))
                    return false;
            }
            return true;
        }
        return false;
    }

    /**
     * {@inheritDoc}
     *
     * @see kodkod.util.ints.IntCollection#addAll(kodkod.util.ints.IntCollection)
     */
    @Override
    public boolean addAll(IntCollection c) {
        boolean modified = false;
        for (IntIterator itr = c.iterator(); itr.hasNext();) {
            if (add(itr.next()))
                modified = true;
        }
        return modified;
    }

    /**
     * {@inheritDoc}
     *
     * @see kodkod.util.ints.IntCollection#retainAll(kodkod.util.ints.IntCollection)
     */
    @Override
    public boolean retainAll(IntCollection c) {
        boolean modified = false;
        for (IntIterator itr = iterator(); itr.hasNext();) {
            if (!c.contains(itr.next())) {
                modified = true;
                itr.remove();
            }
        }
        return modified;
    }

    /**
     * {@inheritDoc}
     *
     * @see kodkod.util.ints.IntCollection#removeAll(kodkod.util.ints.IntCollection)
     */
    @Override
    public boolean removeAll(IntCollection c) {
        boolean modified = false;
        for (IntIterator itr = iterator(); itr.hasNext();) {
            if (c.contains(itr.next())) {
                modified = true;
                itr.remove();
            }
        }
        return modified;
    }

    /**
     * This implementation iterates over this set, removing each element using the
     * <tt>Iterator.remove</tt> operation. Most implementations will probably choose
     * to override this method for efficiency.
     * <p>
     * Note that this implementation will throw an
     * <tt>UnsupportedOperationException</tt> if the iterator returned by this
     * collection's <tt>iterator</tt> method does not implement the <tt>remove</tt>
     * method and this collection is non-empty.
     *
     * @throws UnsupportedOperationException if the <tt>clear</tt> method is not
     *             supported by this collection.
     */
    @Override
    public void clear() {
        for (IntIterator itr = iterator(); itr.hasNext();) {
            itr.next();
            itr.remove();
        }
    }

    /**
     * Returns the result of calling {@linkplain #toArray(int[])} with a freshly
     * constructed array of length this.size().
     *
     * @return this.toArray(new int[size()])
     * @see kodkod.util.ints.IntCollection#toArray()
     */
    @Override
    public int[] toArray() {
        return toArray(new int[size()]);
    }

    /**
     * {@inheritDoc}
     *
     * @see kodkod.util.ints.IntCollection#toArray(int[])
     */
    @Override
    public int[] toArray(int[] array) {
        if (array.length < size()) {
            array = new int[size()];
        }
        int i = 0;
        for (IntIterator itr = iterator(); itr.hasNext();) {
            array[i++] = itr.next();
        }
        return array;
    }
}
